Perimeter Watch
Passive external-perimeter checks as MCP tools: TLS cert expiry, domain renewal, dangling CNAME takeover, CT-log lookalike domains.
Documentation
The four checks
Every run covers the same four checks on every domain you register. Each run produces a one-page brief with evidence.
TLS certificate expiry
Alert when a tracked domain's certificate enters a <14-day expiry window — before a client's site shows an interstitial warning page.
source: Certificate Transparency logs
Dangling DNS / subdomain takeover
Fingerprint subdomains for dangling records that point at claimable services — a known hijack path for staging and legacy subdomains.
source: can-i-take-over-xyz fingerprints
Domain lifecycle
Registrar expiry monitoring: alert when a client domain enters a <21-day renewal window — the failure nobody notices until the site is gone.
source: public registrar records
Lookalike domains
Watch Certificate Transparency logs for typo and hyphen variants of your domains, flagged only when the variant has live DNS.
source: CT logs · DNS resolution
What this is not
Stated plainly, so nobody is surprised:
- No port scans
- No crawling
- No active testing
- No takedowns
- No fixes
- Not a pentest
Passive public metadata only. We read what is already public. If it requires touching your systems, we don't do it.
Pricing
Flat monthly pricing. Cancel any time.
Cancellation stops the next billing cycle. No partial-month refunds. Domain lists and briefs are deleted within 7 days of cancellation — see Terms.
Lite
$9/mo
3 domains
- All four checks on every run
- One-page brief with evidence Start Lite
Your email is collected at checkout by Stripe. Weekly briefs are sent to that address. Nothing else is required.
Agency
$19/mo
10 domains
- All four checks on every run
- One-page brief with evidence Start Agency
Your email is collected at checkout by Stripe. Weekly briefs are sent to that address. Nothing else is required.
Payments are processed by Stripe. Cancel any time — see Terms.
Sample brief
This is a real brief from 2026-09-03 for a real domain, lightly formatted for the web.
● GREEN — all clear ● AMBER — attention needed ● RED — act now
PERIMETER WATCH — BRIEF ────────────────────────────────────────────────── DOMAIN: gasstationpermit.com RUN: 2026-09-03 RATING: ● GREEN — all checks OK COVERAGE: tls · domain_lifecycle · dangling_dns · lookalikes ● tls — OK Evidence: Certificate Transparency log (crt.sh) Certificate expires 2026-11-29 · 87 days remaining Issuer: Let's Encrypt ● domain_lifecycle — OK Registrar expiry 2027-06-18 · 287 days remaining ● dangling_dns — OK 50 subdomains checked · none dangling ● lookalikes — OK 4 variants queried · none registered ────────────────────────────────────────────────── NOT IN SCOPE: port scans · crawling · active testing · takedowns · fixes. Passive public metadata only.
How to start
Get a free one-page perimeter snapshot. Instant, no signup.
No confirmation, no check — we don't run briefs on domains without authority. Nothing is installed, nothing is touched: public records only.